Well the points you stated here are quite convincing enough but look at the negative aspects too, back then you see inter-family dispute here and there, this family won't talk to the members of the other family either because the wives had a misunderstanding or the husbands  of each family are in loggerheads, the duo will each tell their household to never set foot on the other house and this sometimes grows into generational problems. Today, thanks to civilization it's now very rare to have these cases because every family is incharge of only their family and dare not meddle in the affairs if the other family.